Rainbow trout vs. steelhead ???

[bigsteel]

Plumb & MM
Correct, that is why I sourced my post for people to read, so they could see the details of the facts that I was using. So are you saying that the Hood River steelhead and rainbow trout interaction is a fluke or unique behavior to that watershed and that it isn't a fairly safe bet to assume that this is common behavior within most or all watersheds that contain genetically similar steelhead and rainbow trout?

was thinkin the same thing

oh yea,you guys have a great and safe trip.

 

[Modest_Man]

Plumb & MM
Correct, that is why I sourced my post for people to read, so they could see the details of the facts that I was using. So are you saying that the Hood River steelhead and rainbow trout interaction is a fluke or unique behavior to that watershed and that it isn't a fairly safe bet to assume that this is common behavior within most or all watersheds that contain genetically similar steelhead and rainbow trout?

As the article states, "The scientists cautioned that results from one river might not be representative of all steelhead populations. Nevertheless, Christie said, “The importance of trout in maintaining steelhead runs should not be underestimated."

Scientifically, we're taught to not make assumptions. With only one study done extrapolating the findings to any other river would be making pretty large assumptions. Every river is different each contains (or used to contain until widespread planting of generic hatchery stocks) genetically different steelhead populations and until more studies like this are done it's not appropriate to use this study in a blanket statement about all steelhead populations. It's a very neat study and could have some far reaching implications about hatchery and wild steelhead interactions, just more studies need to be done. If more are done and they verify the findings, then it would be more appropriate to classify this as common behavior.

Does that make sense? Just typing "on the fly" so to speak.

 

[Spydeyrch]

As the article states, "The scientists cautioned that results from one river might not be representative of all steelhead populations. Nevertheless, Christie said, “The importance of trout in maintaining steelhead runs should not be underestimated."

Scientifically, we're taught to not make assumptions. With only one study done extrapolating the findings to any other river would be making pretty large assumptions. Every river is different each contains (or used to contain until widespread planting of generic hatchery stocks) genetically different steelhead populations and until more studies like this are done it's not appropriate to use this study in a blanket statement about all steelhead populations. It's a very neat study and could have some far reaching implications about hatchery and wild steelhead interactions, just more studies need to be done. If more are done and they verify the findings, then it would be more appropriate to classify this as common behavior.

Does that make sense? Just typing "on the fly" so to speak.

Very very interesting .... :think: .....

@ everyone:

Thanks for all your input thus far. You have all given some unique perspectives on the subject, and even cited various studies. I appreciate it very much. Thank you.

Let the comments and info keep coming!!! :clap:

-Spydey

 

[Spydeyrch]

I found this article online. I find it quite interesting. It reiterates several points already presented/discussed but I think it is a good source for the discussion that we are all having.

I particularly found it intriguing the following statement taken from the article:

"Among other things, this study proves with no doubt that wild fish and hatchery fish are not the same, despite their appearances," said Michael Blouin, an OSU associate professor of zoology. "Some have suggested that hatchery and wild fish are equivalent, but these data really put the final nail in the coffin of that argument."

Apart from this article, on the right hand side of the article's site, you will find various other articles surrounding the same subject as well as other similar subjects. Very interesting how all of this is playing out. :think:

I particularly found these two articles interesting and somewhat concerning!! :shock:

Hatchery Fish Mask the Decline of Wild Salmon Populations

Hatcheries Change Salmon Genetics After a Single Generation

-Spydey

 

[eggs]

I understand you for sure. But someone could come to a reasonable scientific hypothesis that this is a common behavior within the O. mykiss and be just as correct or incorrect as saying it isn't a common behavior(at this point there is no study saying this doesn't happen in other watersheds). After all, O. mykiss are categorized into a species of Oncorhynchus genus based on behavior, traits and most recently DNA. It is possible for O. mykiss gairdnerii(Columbia Redband Trout) and O. mykiss irideus(Coastal Rainbow Trout) to have different behaviors as they are subspecies. Subspecies are generally based more on location and isolation not behavior, traits and DNA(which would be grounds for a separate species).

 

[Modest_Man]

I understand you for sure. But someone could come to a reasonable scientific hypothesis that this is a common behavior within the O. mykiss and be just as correct or incorrect as saying it isn't a common behavior(at this point there is no study saying this doesn't happen in other watersheds). After all, O. mykiss are categorized into a species of Oncorhynchus genus based on behavior, traits and most recently DNA. It is possible for O. mykiss gairdnerii(Columbia Redband Trout) and O. mykiss irideus(Coastal Rainbow Trout) to have different behaviors as they are subspecies. Subspecies are generally based more on location and isolation not behavior, traits and DNA(which would be grounds for a separate species).

And how do you come to conclusions about a hypothesis? You test it...by looking at other rivers. It's an IF THEN statement. IF resident trout and steelhead commonly interbreed, THEN we can look at rivers all across the Pacific Northwest and find resident trout breeding with steelhead. One river is not a statistically significant population to extrapolate to a whole species. All I (and the article) is saying.

Steelhead are broken up into ESU (evolutionarily significant units), which is why with all the ESA (Endangered Species Act) hubbub the Upper Willamette river steelhead is an ESA listed ESU, while other ESU's (of the same species, O. mykiss) are not.

http://en.wikipedia.org/wiki/Evolutionarily_Significant_Unit I'm not a big fan of Wikipedia but it gives a good outline. Look at Criteria #3.

Frankly, I think you and I are on the same page with this.

 

[eggs]

me too man.. more studies need to be done for sure.

 

[Spydeyrch]

@ Modest_Man

So I am reading that link that you sent me and find it extremely interesting that a steelhead smolt can actually revert back to a parr if it doesn't leave for the seas by a certain time. AMAZING!!!!!! :shock:

Here is the excerpt:

Parr-smolt transformation i n wild and hatchery summer steelhead trout
was size dependent and seasonal i n occurrence. Summer steelhead trout
must be at least 140 - 160 mm in length for the transformation and seaward
migration to occur. The downstream migration of wild and hatchery steelhead
trout occurred from A p r i l through mid-June with the peak of migration from
early to mid-May. Smolts which did not migrate reverted to parr before the
f i r s t of July.


Very interesting .... makes me want to get a degree in this field. :dance:

-Spydey

 

[GDBrown]

So I have questions to add to the mix here.
1. Are there any visual differences between a smolt and a parr?
2. Is this designation strickly based on the direction they are traveling in the river or something else?
3. If you were to take steelhead smolts and put them in a lake do they imediately become parr?
4. If so then when ODFW takes surplus steelhead and puts them into my "Lost Lake" do they become parr as well?

Now you got me wondering as well, but not for long because I'm heading to Utah where all the trout are just trout.

GD

 

[Modest_Man]

1. Are there any visual differences between a smolt and a parr?
Yes. Parr are what you usually see when you catch young trout. Smolt are silvery. Here's a good image, that I shamelessly jacked off the internet. Atlantic salmon, but same difference.

2. Is this designation strickly based on the direction they are traveling in the river or something else? Not based on direction. They undergo a lot of physical changes during the parr-smolt transformation (or smoltification) in order to survive the transition from fresh to salt water. It's all about osmosis really but gets pretty complicated.
3. If you were to take steelhead smolts and put them in a lake do they imediately become parr? Immediately? No, it takes a while to transition from one form to another. Not sure how long though.
4. If so then when ODFW takes surplus steelhead and puts them into my "Lost Lake" do they become parr as well? Surplus as in adults? If they're adult steelhead they cannot become parr, as par is a juvenile form. Over time they I guess they could transition into a resident trout form. I don't really know. Good question.

 

[plumb2fish]

Do Great Lakes Steelhead under-go smoltification?

Would be interesting to see whether red band trout in the willamette watershed and tribs. inter-breed with the native winters...
I do remember reading that it was thought at one time that summer and winter steelhead where one or both species had non-native hatchery supplementation, were thought to inter-breed, but there was no genetic link between the 2 when tested...possibly hood river study as well.

 

[brandon4455]

that is a very good question, i would like to know that answer s well!! although id like to point out those fish are just lake run rainbow trout not steelhead. a rainbow that does not go to the salt is just a bow :lol:

 

[Modest_Man]

Do Great Lakes Steelhead under-go smoltification?

Would be interesting to see whether red band trout in the willamette watershed and tribs. inter-breed with the native winters...
I do remember reading that it was thought at one time that summer and winter steelhead where one or both species had non-native hatchery supplementation, were thought to inter-breed, but there was no genetic link between the 2 when tested...possibly hood river study as well.

I would assume they do, then migrate to the lake, and then reverse the process. Though I can't find literature to back it up.

 

[Spydeyrch]

So then I have a question. Being that steelhead and salmon go through a smoltification process to head out to sea, do sea-run cutthroats, sea-run browns, and sea-run brookies go through a smoltification process in order to go out to sea? :think:

-Spydey

 

[Modest_Man]

Read pages marked 53 and 59. Or read all 329 pages, it's good info! (I just use the search function) http://www.nwfsc.noaa.gov/publications/techmemos/tm37/cutthroat.pdf Some do, but most do not. Seems that if the fish just hangs out in estuaries (like most sea-run cutthroat do) they don't undergo full smoltification, as it's a less saline environment.

Also, the page marked 49 goes into some of the why smoltification occurs that we discussed in PMs.

Also, read pages 49, 50, and 51 in this book. If the link works. http://books.google.com/books?id=o2...=onepage&q=brook trout smoltification&f=false

 

[Big3d]

So, I'm pretty dense... if they stock adult steelhead into lost lake have they been sea-run? Otherwise they would simply be adult Rainbows right? this whole thread has made my head spin...

 

[the_intimidator03]

So, I'm pretty dense... if they stock adult steelhead into lost lake have they been sea-run? Otherwise they would simply be adult Rainbows right? this whole thread has made my head spin...

If they stock adult steelhead into a lake, lost lake included, they ARE sea run. Most places that I know that have steelhead planted into a pond/lake are tagged with an orange spaghetti noodle type tag near the dorsal fin